Australian Antarctic Division: Leading Australia’s Antarctic Program

Glaciology Loose Ends

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This week at Casey: 18 February 2011

This week saw the final piece of glaciology fieldwork for the season: a trip to Law Dome summit. This is part of project 3064, run by Dr Andrew Smith of the Australian Nuclear Science and Technology Organisation (ANSTO) in collaboration with colleagues at the Australian Antarctic Division.

The project has at its heart a focus on measuring isotopes of the element beryllium in ice cores. The abundance of these naturally occurring radioactive isotopes is connected with the activity of the Sun, and measurements in ice cores are used to estimate past variation in solar radiation and its relation to climate. Beryllium-10 is long-lived (1.6 million years) which is why it is a useful indicator of past climate. Another isotope, beryllium-7 has a half life of just 53 days, which isn’t of much use in a long-term climate record, but can be used to help understand more about the long-lived beryllium-10. Because it is created by the same processes as beryllium-10, it can be used as a timer/stopwatch to track how it is transported in the atmosphere and locked into the snowpack.

So a team of four set about a marathon expedition on Monday morning – driving seven hours in a Hagg to the Dome Summit South (DSS) site, working seven hours and then driving another seven hours down the hill to Casey. Plant inspector Steve Macaulay, field training officer Greg Barras and glaciologists Jason Roberts and Tas van Ommen were the slightly masochistic individuals who made the trip and were greeted by –20ºC conditions and 10–15 knot winds at DSS.

While onsite, they drilled cores to get beryllium-10 samples, extending their record to 11 years, and significantly including the recent year in which the Sun has been unusually quiet. They also collected samples from a 60cm deep snow pit for beryllium-7. These samples, because of the short 53 day half-life, are to be returned to Australia on the first available airbus service.